Why is this important?

Patients with COM do not often present as emergencies, but are seen quite frequently in outpatients and emergency clinics

Symptoms and signs of COM should prompt referral to a specialist colleague for further (elective) management, to avoid progression and complications

Patients who are elderly, with diabetes or other causes of immunosuppression are at risk of life-threatening complications

When to involve the ENT Registrar

If there are red flags of an acute complication of COM (see above), assess and treat the patient and contact the registrar

If you think a person may have COM, discuss this with a registrar during working hours and organise an expedited outpatient appointment

Introduction

Chronic otitis media (COM) is a condition commonly seen in ENT clinics. It has two broad types, mucosal and squamous, and encompasses the disease known as cholesteatoma. It is also known by several older terminologies, such as chronic suppurative otitis media, cholesteatoma, and ‘attico-antral’ versus ‘tubo-tympanic’ disease.

Pathology

The root cause of COM is unclear in many cases. The disease takes two main forms, and is classified as below:

Mucosal COM

Results from a perforation in the tympanic membrane (which may have been caused by acute otitis media, trauma, grommet insertion etc). This allows the middle ear to become chronically infected, leading to mucosal hypertrophy and chronic discharge

If a perforation is discharging, this is known as active mucosal COM. A dry perforation is therefore technically known as inactive mucosal COM

It is important to remember that the mucosal lining of the mastoid air cells is continuous with the middle ear, and is generally affected in the same way.

The tympanic membrane may become retracted, commonly in the postero-superior segment (the pars flaccida or attic). If the retraction pocket is deep, keratinous debris begins to accumulate in the pocket rather than making its way out of the ear canal. This is associated with chronic infection/inflammation and may lead to a foul-smelling persistent discharge from the affected ear.

This process may lead to a mass within the pocket called a cholesteatoma.

A cholesteatoma is a cystic, inflammatory mass of keratinising stratified squamous epithelium. Microscopically, there is keratin debris, granulation tissue, a chronic inflammatory infiltrate and cholesterol clefts. It was probably originally named cholesteatoma ('fat tumour') because macroscopically, it appears white and waxy.

A cholesteatoma can go on to cause erosion of the middle-ear structures, the inner ear, and the surrounding temporal bone.

Assessment and recognition

History

The most common symptom of chronic otitis media (mucosal or squamous) is chronic ear discharge(otorrhoea >6 weeks), which may have a strong odour. This may be intermittent or constant, and often a patient will have had a substantial period of symptoms before referral to ENT.

The patient may complain of a persistent feeling of fullness in the affected ear(s).

Many patients have a degree of hearing loss in the affected ear(s). This is more likely to be conductive in nature, due to mucosal inflammation, the presence of discharge, and erosion of the ossicles. Less commonly, the presence of toxic by-products of inflammation or erosion of the inner ear may lead to sensorineural hearing loss.

Dizziness or low-grade imbalance is quite common. Severe rotatory vertigo may be due to erosion of the balance organ (labyrinthine fistula).

Pain and fever are uncommon, but if present should raise concern of a complication of COM (see below), especially if associated with neurological symptoms or drowsiness.

Rarely, the facial nerve (CN VII) may be affected in its middle ear (horizontal) segment, leading to facial palsy.

Examination

A thorough examination of the ear drum should reveal a perforation, with or without discharge, or a retraction pocket with or without squamous debris.

It is very important to examine the patient with a microscope. This gives superior 3-D visualisation of the tympanic membrane, and allows microsuction. It is essential to remove debris and discharge to assess the ear fully. This process can be painful in the presence of active disease, and may need to take place under general anaesthesia.

Examine the mastoid, external ear (for signs of previous surgery) and the function of the facial nerve.

The chronic inflammation of COM and the erosive properties of a cholesteatoma may lead to destruction of adjacent structures and/or spread of infection through natural weaknesses in the surrounding bone. Complications of COM are relatively uncommon, but must be excluded when examining a patient with chronic ear discharge. They can be classified into intracranial and extracranial.

Intracranial

Meningitis

Abscess: may be extradural, subdural, or within the temporal lobe.

Osteomyelitis of the apex of the petrous temporal bone may lead to deep pain and cranial nerve symptoms (particularly V and VI) – this is also known as Gradenigo’s syndrome.

Ossicular discontinuity – erosion of the ossicles leads to sensorineural hearing loss. It preferentially affects the long process of the incus and the stapes superstructure

Sensorineural hearing loss

Facial nerve palsy

Labyrinthine fistula (causing vertigo)

Temporal bone osteomyelitis

Immediate and overnight management

If there is a complication of COM, then treat it urgently using the information under acute otitis media complications as a guide. Discuss the case with the registrar.

Suspected COM with no signs of complication should be investigated and treated in main ENT outpatients.

Prescribe some antibiotic/steroid drops to the patient along with any symptomatic treatment.

Explain that you are trying to dry the ear out somewhat and that expert opinion is required.

Further management

The management strategy in COM varies between clinicians. However, in an ear with persistent or progressive disease (whether squamous or mucosal), management is generally aimed at eradicating all diseased tissue in the middle ear and mastoid.

This part aims to give a brief overview of this large, complex area of ENT practice only, as it is not immediately relevant out-of-hours.

Medical

Disease activity in COM may be mild or intermittent; an operation may also be unsafe or unwanted. In these patients, regular attendance to clinic for microsuction and/or antibiotic ear drops may be preferred. Many patients will undergo a period of active observation with medical management following their initial presentation.

Microsuction and ear drops may lead to disease remission in some patients: producing a clean retraction pocket, or a consistently dry perforation. The decision on proceeding to surgery for these patients is complex and controversial, and beyond the scope of this guide.

In patients with persistent discharge through a perforation, an expanding retraction pocket, or persistent cholesteatoma, surgery is usually the next step.

Surgical

Surgery in COM aims to eradicate all diseased tissue in the middle ear cavity and mastoid air cells, producing a clean and dry (“safe”) ear, with an intact tympanic membrane. This is performed to arrest the disease process and to prevent complications.

A successful operation may occasionally bring about an improvement in hearing; however it is very important to explain to patients that this is not the reason for operating. The priority is to produce a safe ear (ie to prevent complications). Surgery may not improve hearing, and may even need to be performed at the expense of residual hearing.

It is essential that all patients undergoing middle ear surgery have a recent pre-operative hearing test. Many surgeons also require a CT of the temporal bones before undertaking mastoidectomy/tympanoplasty or myringoplasty.

Surgery can take several forms, ranging from conservative to radical and is outside the scope of this article.